Question

Define oxyacid. Give two examples.

Short answer

Answer: An oxyacid is a type of acid that contains a central atom (usually a nonmetal), an oxygen atom, and hydrogen atom(s) bonded together, with the hydrogen atoms attached to the oxygen atoms. Oxyacids exhibit acidic properties due to the hydrogen atoms dissociating as protons (H+ ions) in aqueous solutions. Two examples of oxyacids are sulfuric acid (H2SO4), with sulfur as the central atom, and phosphoric acid (H3PO4), with phosphorus as the central atom.

Step-by-step solution

Definition of Oxyacid

An oxyacid is a type of acid that contains a central atom (usually a nonmetal), an oxygen atom, and hydrogen atom(s), bonded together. The H atom(s) in oxyacids are attached to the oxygen atom(s), making them hydrogens that can dissociate as protons (H+ ions) in aqueous solutions, and thus exhibit acidic properties.

Characteristics of Oxyacids

Oxyacids often have the general formula H_aXO_b, where X is the central atom (typically a nonmetal), a is the number of hydrogen atoms, and b is the number of oxygen atoms. At least one hydrogen atom is attached to an oxygen atom in the molecule. When oxyacids dissolve in water, they release H+ ions, increasing the acidity of the solution.

Example 1: Sulfuric Acid (H2SO4)

In sulfuric acid, sulfur (S) is the central atom, surrounded by four oxygen (O) atoms and accompanied by two hydrogen (H) atoms bonded to the oxygen atoms. It has the formula H2SO4. In aqueous solution, sulfuric acid can dissociate to produce H+ ions, which gives it its acidic properties.

Example 2: Phosphoric Acid (H3PO4)

In phosphoric acid, phosphorus (P) is the central atom, surrounded by four oxygen (O) atoms and accompanied by three hydrogen (H) atoms bonded to the oxygen atoms. It has the formula H3PO4. In aqueous solution, phosphoric acid can dissociate to produce H+ ions, displaying its acidic characteristics.

Key concepts

Acidic Properties

Understanding the acidic properties of compounds is crucial in chemistry, especially when studying acids and their behaviors. Oxyacids are a class of acids characterized by their ability to donate protons (hydrogen ions, H+) when dissolved in water. This process is called ionization or dissociation and is the fundamental property that gives oxyacids their acidic nature.

The amount of H+ ions an oxyacid can produce influences its strength as an acid. Stronger oxyacids dissociate completely, releasing all possible H+ ions into the solution, while weaker oxyacids partially dissociate, releasing fewer H+ ions. The acidic properties of an oxyacid can be influenced by several factors, such as the electronegativity of the central atom and the number of oxygen atoms bonded to it, as the oxygen can draw electron density away from the bond between hydrogen and itself, facilitating the release of the H+ ion.

The environment in which the oxyacid is dissolved also affects its behavior. For instance, in an aqueous solution, the presence of water molecules plays a key role in stabilizing the H+ ions that are released.

Chemical Formula of Oxyacids

The chemical formula of an oxyacid can be represented by the general formula \( H_aXO_b \), where \( a \) represents the number of hydrogen atoms capable of dissociating into protons, \( X \) is a central atom (often a nonmetal), and \( b \) expresses the number of oxygen atoms bonded to the central atom and the hydrogen.

In crafting these formulas, it's important to note that the hydrogen atoms in oxyacids are specifically attached to oxygen atoms, which is central to understanding their intrinsic acidic characteristics. The bond between the hydrogen and oxygen within the oxyacid is not as stable as other bonds, which allows for easier dissociation of hydrogen as H+ ions.

These formulas also imply an underlying structure to the molecules, dictating the arrangement of atoms within and aiding in predicting the strength and properties of the acid. For example, the presence of multiple oxygen atoms can increase the acid's ability to dissociate, thereby making it stronger.

Examples of Oxyacids

There are numerous examples of oxyacids, and many are commonly found in laboratory and industrial settings as well as in everyday life. Two key examples include sulfuric acid \( H_2SO_4 \) and phosphoric acid \( H_3PO_4 \).

• Sulfuric Acid (H₂SO₄): It is a strong acid used in a variety of applications, such as in batteries and for industrial processes. Its structure consists of two hydrogen atoms, one sulfur atom, and four oxygen atoms. In an aqueous solution, it can dissociate to release two H+ ions.
• Phosphoric Acid (H₃PO₄): Commonly used in food processing and as a rust inhibitor, phosphoric acid has a structure comprising three hydrogen atoms, one phosphorus atom, and four oxygen atoms. It can release three H+ ions when dissolved in water, but it does so in stages and is considered a weaker acid than sulfuric acid.

Countless other oxyacids are utilized across various sectors, from nitric acid in fertilizer manufacturing to acetic acid in vinegar. Each has its unique formula and properties, but they all share the common trait of containing hydrogen, oxygen, and a central nonmetal atom, enabling them to exhibit acidic behavior in solutions.